2 files changed, 20 insertions, 56 deletions

diff --git a/src/drivers/intel/gma/acpi.c b/src/drivers/intel/gma/acpi.c
index 3f71a5ea84..d3fb69dec8 100644
--- a/src/drivers/intel/gma/acpi.c
+++ b/src/drivers/intel/gma/acpi.c
@@ -102,39 +102,38 @@ drivers_intel_gma_displays_ssdt_generate(const struct i915_gpu_controller_info *
 		}
 
 		/*
-		Method(_DCS, 0)
-		{
-			Return (^^XDCS(<device number>))
-		}
+		 * _DCS, _DGS and _DSS are required by specification. However,
+		 * we never implemented them properly, and no OS driver com-
+		 * plained yet. So we stub them out and keep the traditional
+		 * behavior in case an OS driver checks for their existence.
+		 */
+
+		/*
+		  Method(_DCS, 0)
+		  {
+			Return (0x1d)
+		  }
 		*/
 		acpigen_write_method("_DCS", 0);
-		acpigen_emit_byte(0xa4); /* ReturnOp.  */
-		acpigen_emit_namestring("^^XDCS");
-		acpigen_write_byte(i);
+		acpigen_write_return_integer(0x1d);
 		acpigen_pop_len();
 
 		/*
-		Method(_DGS, 0)
-		{
-			Return (^^XDGS(<device number>))
-		}
+		  Method(_DGS, 0)
+		  {
+			Return (0)
+		  }
 		*/
 		acpigen_write_method("_DGS", 0);
-		acpigen_emit_byte(0xa4); /* ReturnOp.  */
-		acpigen_emit_namestring("^^XDGS");
-		acpigen_write_byte(i);
+		acpigen_write_return_integer(0);
 		acpigen_pop_len();
 
 		/*
-		Method(_DSS, 1)
-		{
-			^^XDSS(0x5a, Arg0)
-		}
+		  Method(_DSS, 1)
+		  {
+		  }
 		*/
 		acpigen_write_method("_DSS", 1);
-		acpigen_emit_namestring("^^XDSS");
-		acpigen_write_byte(i);
-		acpigen_emit_byte(0x68); /* Arg0Op.  */
 		acpigen_pop_len();
 
 		acpigen_pop_len();
diff --git a/src/drivers/intel/gma/acpi/common.asl b/src/drivers/intel/gma/acpi/common.asl
index 3932a88e87..09d48a20e0 100644
--- a/src/drivers/intel/gma/acpi/common.asl
+++ b/src/drivers/intel/gma/acpi/common.asl
@@ -35,11 +35,6 @@
 	/* Display Output Switching */
 	Method (_DOS, 1)
 	{
-		/* Windows 2000 and Windows XP call _DOS to enable/disable
-		 * Display Output Switching during init and while a switch
-		 * is already active
-		 */
-		Store (And(Arg0, 7), DSEN)
 	}
 
 	/*
@@ -80,33 +75,3 @@
 			XBCM (DerefOf (Index (BRIG, Local0)))
 		}
 	}
-
-	/* Device Current Status */
-	Method(XDCS, 1)
-	{
-		TRAP(1)
-		If (And(CSTE, ShiftLeft (1, Arg0))) {
-			Return (0x1f)
-		}
-		Return(0x1d)
-	}
-
-	/* Query Device Graphics State */
-	Method(XDGS, 1)
-	{
-		If (And(NSTE, ShiftLeft (1, Arg0))) {
-			Return(1)
-		}
-		Return(0)
-	}
-
-	/* Device Set State */
-	Method(XDSS, 1)
-	{
-		/* If Parameter Arg0 is (1 << 31) | (1 << 30), the
-		 * display switch was completed
-		 */
-		If (LEqual(And(Arg0, 0xc0000000), 0xc0000000)) {
-			Store (NSTE, CSTE)
-		}
-	}